Field of the Invention
The invention pertains to fuel-fired heat exchanger using a combustion chamber and heat transfer radiators.
Background Art
Traditional direct-vent heat exchangers comprise a water tank, a combustion chamber where a gas fuel burns to heat air, and a flue system in which air circulates in a radiator surrounding by water, the radiator transferring the heat carried by the air to the water. These systems often have a sealed combustion chamber and blowers to assist air flow through the system.
Heat exchangers are known in the industry; in particular, water heater construction techniques are well established, with many types of heater combustion chambers. The prior art is rich in very old construction and patented approaches to the many difficulties of designing effective heat exchangers, many of which include: the transfer of heat which comes from a combustion chamber to the water, condensation problems, heat transfer efficiency, and the challenge of a system that can be kept clean over the life of the system.
An overview of the prior art includes patented water tanks, e.g., U.S. Pat. No. 7,500,454, heat chambers, e.g., U.S. Pat. No. 7,946,257, unique duct and flue systems e.g., U.S. Pat. No. 7,992,526 and U.S. Pat. No. 7,997,236, fin-equipped metal fins to increase efficiency, e.g., U.S. Pat. No. 7,836,856, and pipe assemblies to conduct the heat from the air to water, e.g., U.S. Pat. No. 7,434,545, U.S. Pat. No. 7,458,340, and U.S. Pat. No. 7,523,721.
As these and other patents show, inventors and the heat exchanger industry continues to struggle in building a more efficient water heater, continuously looking for higher efficiency, longer productive life, less expensive manufacturing costs, and less frequent cleaning requirements.